Subscribe cancelled by Notify

At the top of each topic I have a “subscribe” link. Clicking it subscribes me to the topic so I get emails when new posts are added.

At the bottom of each topic, with the “Reply” option is another link “Notify me of follow-up replies via email”.

I have found that when I am subscribed to a topic, if I reply and do not tick “Notify me of follow-up replies via email”, then my subscription to that topic is cancelled (top link changes to ‘unsubscribed’, and future responses are not notified to me by email.

Surely this isn’t the intended result? Are the two options actually necessary?

I can’t confirm a specific date though we do have bbPress 2.5.3 to ship in a couple of days, we just need to make sure what we have ready is good to ship and that nothing else pops up as an issue from what we have ready to ship.